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Possible meteor explosion in Northeast Oshawa.

PETERBOROUGH -- Social media came alive late Sunday afternoon with numerous reports of a loud boom and shaking felt in an area stretching from north of Peterborough south to the lakeshore in Cobourg, Port Hope, Durham Region, Scarborough and east Toronto.

Several of those tweeting also reported seeing a bright flash in the sky about 4:20 p.m., leading to speculation that a meteor had entered the atmosphere and crashed to earth. Among the many who reported a fireball preceding the boom was Michael Kasaboski, who tweeted @mykawartharelly that he "spotted it while driving along the 401."

There were no immediate reports of injuries or any damage, nor any indication that anything had struck the ground.

"I was visiting my mom (at St. Joseph's at Fleming) and it felt like some big door closed somewhere in the building and her curtains went flying outward," Camille Parent told myKawartha.com

”There are dash-cam videos I’ve seen already posted to the internet that...clearly show what I would say is unequivocally a meteor,” said Peter Brown, a professor at the University of Western Ontario who studies meteors and meteorites.

Many Ontarians took to social media or contacted the American Meteor Society to report either a flash of light or a loud rumble.

The reports came in from various southern Ontario communities and parts of the United States.

The meteor society posted a comment from a person who said he was from Toronto and described a bright flash.

"It was as fast as a shooting star," said the poster who identified himself as "Doug C."

"It was as bright if not brighter than a lightning bolt."

Dana Petrillo, of Cobourg, tweeted that her house vibrated and that she first thought there had been an earthquake or explosion.

"It was a really low rumble that just reverberated through the walls. It really wasn't a shaking, like in an earthquake, but more like a wave. It really did feel like an explosion," she said in an email.

Most of the equipment the university has to track meteors was not in operation Sunday afternoon, but a series of microphones the university has in place did detect a shockwave, Brown said.

Based on the data and the eyewitness reports it appears the shockwave occurred in the area of Peterborough, Ont., and its characteristics allowed for an estimate of the size of the meteor, said Brown.

”The energy is somewhere in the order of a few tens of tons of TNT explosive equivalent," he said in an interview from London, Ont. Sunday night. "That would translate into something on the order of half to one metre in diameter and that’s going to be a mass of ....a few metric tons.”

It's possible some fragments hit the ground, Brown added.

”This clearly was a pretty massive event, lots of mass, so on that basis alone I think we have a pretty good chance that meteorites would make it to the ground,” he said.

The odds of fragments hitting the ground depend on how fast the meteor was travelling — a relatively slow moving fireball would make it more likely that some meteorites may be found.